Japanese Laid-Open Patent Application No. 2005-128936 discloses a finger authentication device including a guide part for setting a finger's position, a light source part for applying transmitted light to the finger, an imaging part for imaging the transmitted light, and an authenticating part for authenticating the image taken by the imaging part. The guide part includes an authenticated and a non-authenticated finger placement guide part for setting fingers that are note to be authenticated.
Japanese Patent No. 3916647 discloses a biometric device including a transparent plate formed of glass or plastic for placing an object which is a finger of a person to be authenticated downwards in the figure, an illumination device for fingerprint photographing, an illumination device for vein photographing, and imaging apparatus provided with a zoom optical system. The imaging apparatus is provided with an object field depth expansion system with an optical wave surface modulation element and an image processing part. In authentication, image data generated in an image processor of the object imaged by an imaging device and present reference authentication data are compared, and the size of an object image fetched by the imaging device is adjusted by driving the zoom optical system.
Japanese Laid-Open Patent Application No. 2006-11988 discloses an image capturing apparatus for palm authentication which facilitates correct placement of a user's hand. In order to correctly guide the palm of a user into an image capturing region, on one side of a non-contact sensor unit for image capturing the palm, a front face guide is provided for supporting a wrist having a hand to be captured by the non-contact sensor unit. The front face guide enables guiding of the palm naturally to an image capturing region of the sensor unit. Because of the front face guide supports the wrist, the palm can correctly be positioned within the image capturing region of the sensor unit. A rear guide may also be provided, on the other side of the non-contact sensor unit, for supporting the fingers of the hand.